Piazza NavonaFrom an air view, the arena-like shape of Piazza Navona can be easily noticed. As a matter of fact, the piazza was built on the Stadium of Domitian, whose ruins can still be admired in the adjacent church of Sant'Agnese in Agone. The church, designed by the great architect Francesco Borromini, is an excellent example of the Roman Baroque architecture. In Piazza Navona are three fountains: Fontana del Moro, Fontana di Nettuno and in the centre of the square Bernini's magnificent Fontana dei Fiumi. Four allegorical statues portray the Nile, the Ganges, the Danube and the Rio de la Plata, symbolizing the four corners of the world. Traditionally, from the beginning of December till the Epiphany, this piazza is occupied by stalls selling sweets and toys.

Brief historical outlineAround 86 A.D., Emperor Domitian had a stadium built on a pre-existing amphitheatre of Nero's time and over the centuries the square became a place for games, tournaments and processions. From the 17th to the 19th centuries the square used to be flooded to allow the ships of princes and prelates to parade in a background of fireworks.

Stadium Domitiani: the stadium which Domitian built in the campus Martius for athletic contests (Suet. Dom. 5; Eutrop. vii.23; Chron. 146; Hieron. ad a. Abr. 2105; Not. Reg. IX). After the Colosseum was injured by fire in 217, it was used for several years for gladiatorial combats (Cass. Dio lxxviii.25). Its arcades were occupied by brothels (Hist. Aug. Elag. 26) as were those of the circus Maximus. The stadium was restored by Alexander Severus (id. Alex. 24), and hence was sometimes called in the Middle Ages circus Alexandri (Ordo Bened. 143).1 In the fourth century it was one of the buildings that are said to have aroused the special admiration of Constantius (Amm. Marcell. xvi.10.14). It had 30088 loca (Cur.), that is, seats for about 15,000 spectators (HJ 593). According to the legend, S. Agnes met a martyr's death in the brothels in the arcades of this stadium, and in her honour a church was built in the ninth century in the middle of the cavea on the west side, which was afterwards known as S. Agnese in Agone or de Cryptis Agonis (Arm. 383‑384; HCh 168º), the word agon being used both for a gymnastic contest and for the place of its celebration (Lydus, de mens. iv.30;2 Pr. Reg. 171). There was also a church of S. Nicolas de Agone (HCh 389 — that of S. Caterina de cryptis agonis (cf. Arm. 388) never existed).• The Piazza Navona, the largest in the city, now called officially Circo Agonale, preserves almost exactly the shape and size of the stadium. The piazza itself corresponds closely with the arena, the length of which seems to have been about 250 metres, and the surrounding buildings stand on the ruins of the cavea. Under the church of S. Agnese remains of brick and concrete walls, travertine pilasters and the seats of the cavea are still to be seen, and other traces have been found beneath the existing buildings at other points. For excavations in the sixteenth century, see LS ii.228‑231; iii.224‑225; iv.190; LR 498‑500; HJ 592‑594. For the obelisk of Domitian which was erected there in 1651, see Obelisci Isei Campensis (4). Cf. also Mem. L. 5.xvii.521.